Document Detail

Application of negative expiratory pressure during expiration and activity of genioglossus in humans.
MedLine Citation:
PMID:  9480971     Owner:  NLM     Status:  MEDLINE    
The application of negative expiratory pressure (NEP) at end expiration has been shown to cause reflex-mediated activation of the genioglossus muscle in awake humans. To test whether a reflex contraction of pharyngeal dilator muscles also occurs in response to NEP applied in early expiration, the effect on genioglossus muscle reflex activity of NEP pulses of 500 ms, given 0.2 s after the onset of expiration and during the end-expiratory pause, was assessed in 10 normal awake subjects at rest. The raw and integrated surface electromyogram of the genioglossus (EMGgg) was recorded with airflow and mouth pressure under control conditions and with NEP ranging from -3 to -10 cmH2O. Intraoral EMGgg was also recorded under the same experimental conditions in two subjects. The application of NEP at the end-expiratory pause elicited a consistent reflex response of EMGgg in seven subjects with a mean latency of 68 +/- 5 ms. In contrast, when NEP was applied at the onset of expiration, EMGgg reflex activity was invariably observed in only one subject. No relationship was found between steady increase or abrupt fall in expiratory flow and the presence or the absence of a reflex activity of genioglossus during sudden application of NEP at the beginning of expiration. Our results show that a reflex activity of genioglossus is elicited much more commonly during application of NEP at the end rather than at the onset of expiration. These findings also suggest that when NEP is applied in early expiration to detect intrathoracic flow limitation the absence of upper airways narrowing does not imply the occurrence of a reflex-mediated activation of genioglossus and vice versa.
C Tantucci; S Mehiri; A Duguet; T Similowski; I Arnulf; M Zelter; J P Derenne; J Milic-Emili
Publication Detail:
Type:  Clinical Trial; Journal Article    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  84     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1998 Mar 
Date Detail:
Created Date:  1998-04-09     Completed Date:  1998-04-09     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1076-82     Citation Subset:  IM    
Clinica di Semeiotica Medica, University of Ancona, 60020 Ancona, Italy.
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MeSH Terms
Air Pressure*
Airway Resistance / physiology
Middle Aged
Reflex / physiology
Respiratory Mechanics / physiology*
Respiratory Muscles / innervation,  physiology*

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